I have a problem finding Mars!

[Moonshed]

I have a Celestron 8” and I’m using a 2x Barlow and a ZWO ASI234MC colour camera. The mount is an EQ5. I have aligned my Telrad Red Dot finder as close to perfection as possible.
If I use the GOTO it doesn’t find it so it does not appear on the FireCapture screen, even with using the spiral search function, even though it looks ok in the Telrad. If I manually line it up dead centre in the Telrad it still doesn’t find it until I have spent ages playing around with the hand controller buttons whilst watching the screen. The difference in movement around apparent dead centre is incredibly small but very significant.

The Telrad, although great for finding objects for eyepiece observing, just doesn’t cut it for the accuracy required for photography.

There must be an easier way of locating a planet, surly?

Any ideas anyone?  because it’s driving me nuts and and I’m trying to get the hang of my new Zwo.

[happy-kat]

I'd try using an eyepiece first, then use a high powered one get Mars centered then swap for the camera.

[Peter Drew]

+1    🙂

[Davey-T]

As Kate said use eyepiece, long / short then carefully swop for camera having previously noted where camera focuses.

You can even try without an eyepiece and nudge scope around until you see a big orange donut the refine it from there.

You only have to breath on the scope and it hops out of the Firecapture FOV.

If you're feeling flush you could buy a Baader flip mirror.

Dave

[fifeskies]

+1 for a wide field eyepiece first , then a narrower one , then swap to camera.

 

That said if you are well polar aligned , and do a star calibration , you should be there with a GOTO.

Do you use plate solving to make sure the scope is properly calibrated for GOTO position , one of the handy things in APT. (solve then sync).

I love my Telrad but its not a precision instrument for AP. I use my Telrad and a RACI finder to get right on target.

(and of course you need to periodically align Telrad and main scope (and RACI) )

[Moonshed]

2 hours ago, Davey-T said:

As Kate said use eyepiece, long / short then carefully swop for camera having previously noted where camera focuses.

You can even try without an eyepiece and nudge scope around until you see a big orange donut the refine it from there.

You only have to breath on the scope and it hops out of the Firecapture FOV.

If you're feeling flush you could buy a Baader flip mirror.

Dave

Thank you. The only problem I have with that is the focussing, which can be very challenging. If I focus for the EPs then when I swap over with the camera it will obviously be out of focus and need refocusing. Hopefully though if Mars is still centred, a bit iffy me thinks  after the fiddling around, I will see a faint orange donut and take it from there.

I certainly give it a try.

What do you mean by “having previously noted where camera focuses.”? Because that’s the problem, how can you tell?

[Peter Drew]

I made an adapter for the eyepiece so that the focus position for the eyepiece and the camera were identical.    🙂

[Davey-T]

9 minutes ago, Moonshed said:

What do you mean by “having previously noted where camera focuses.”? Because that’s the problem, how can you tell?

Tricky with SCT, I try to count the number of turns of the focuser knob with mine to try and get it back to somewhere near after swopping from eyepiece to camera.

As usual to make life easier you can throw money at it, I've got an electronic focuser on my Meade SCT which makes it a doddle to get focus once it's near, moving the main focus knob on mine throws Mars completely out of the FOV.

Dave

As Peter said, if you're using 1.25 gear you could use parfocal rings so that you don't have to move the focus.

Edited November 7, 2020 by Davey-T

[Moonshed]

1 hour ago, Davey-T said:

Tricky with SCT, I try to count the number of turns of the focuser knob with mine to try and get it back to somewhere near after swopping from eyepiece to camera.

As usual to make life easier you can throw money at it, I've got an electronic focuser on my Meade SCT which makes it a doddle to get focus once it's near, moving the main focus knob on mine throws Mars completely out of the FOV.

Dave

As Peter said, if you're using 1.25 gear you could use parfocal rings so that you don't have to move the focus.

I already use an electronic focuser as it’s a must for astrophotography but I do wish they came with a screen with markers from min to max so you could make a note of different focus positions, save a hell of a lot of time and trouble.

[michael8554]

I too found framing impossible, until I added a Flip Mirror:

https://www.amazon.co.uk/Omegon-Syncfocus-flip-mirror-planetary-cameras/dp/B01IQOI8CI/ref=asc_df_B01IQOI8CI/?tag=googshopuk-21&linkCode=df0&hvadid=218087202227&hvpos=&hvnetw=g&hvrand=200631285328338290&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006463&hvtargid=pla-378459776861&psc=1

When correctly set up, a reticle eyepiece in the top port is used to locate and centre the target.

Then the mirror is flipped up so that the target is on the camera.

It depends on the eyepiece and camera both being in focus, set up on a distant object during the day.

Then adjust the SCT focus only on the moon for infinity focus of the camera, and fine tune on your target.

Michael

[Moonshed]

10 hours ago, michael8554 said:

I too found framing impossible, until I added a Flip Mirror:

https://www.amazon.co.uk/Omegon-Syncfocus-flip-mirror-planetary-cameras/dp/B01IQOI8CI/ref=asc_df_B01IQOI8CI/?tag=googshopuk-21&linkCode=df0&hvadid=218087202227&hvpos=&hvnetw=g&hvrand=200631285328338290&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006463&hvtargid=pla-378459776861&psc=1

When correctly set up, a reticle eyepiece in the top port is used to locate and centre the target.

Then the mirror is flipped up so that the target is on the camera.

It depends on the eyepiece and camera both being in focus, set up on a distant object during the day.

Then adjust the SCT focus only on the moon for infinity focus of the camera, and fine tune on your target.

Michael

That looks to be the perfect solution. I followed your link and was pleased to find it only cost £60, I shall be ordering one!

Thanks for the info.

Edited November 8, 2020 by Moonshed

[PeterCPC]

+1 for flip mirror.

[michael8554]

The Flip Mirror is fine for your SCT, which has a huge range of focus, but for a Newtonian will probably be too "thick" for focus to be obtained.

Michael

[Moonshed]

3 hours ago, michael8554 said:

The Flip Mirror is fine for your SCT, which has a huge range of focus, but for a Newtonian will probably be too "thick" for focus to be obtained.

Michael

Hi Michael

I have ordered the flip mirror and it arrives Tuesday. I am guessing that an illuminated reticle eyepiece is pretty much essential for this and have looked at some. I found this one on Amazon which is really cheap at £30 delivered and I feel it will be good enough for the job. What do you think?

https://www.amazon.co.uk/Astromania-Illuminated-Reticle-Telescope-Eyepiece/dp/B085DL11YT/ref=sr_1_5?crid=30HKTGZQGRHGP&dchild=1&keywords=reticle+eyepiece+telescope&qid=1604850610&sprefix=Reticke%2Caps%2C159&sr=8-5

Thanks again.

Keith

 

[dark knight]

Since your already using a laptop (presumptuous of me i know) why not try plate solving and APT or nina, im totally converted to using plate solving now

[Planitair]

On 07/11/2020 at 13:55, Moonshed said:

I have a Celestron 8” and I’m using a 2x Barlow and a ZWO ASI234MC colour camera. The mount is an EQ5. I have aligned my Telrad Red Dot finder as close to perfection as possible.
If I use the GOTO it doesn’t find it so it does not appear on the FireCapture screen, even with using the spiral search function, even though it looks ok in the Telrad. If I manually line it up dead centre in the Telrad it still doesn’t find it until I have spent ages playing around with the hand controller buttons whilst watching the screen. The difference in movement around apparent dead centre is incredibly small but very significant.

The Telrad, although great for finding objects for eyepiece observing, just doesn’t cut it for the accuracy required for photography.

There must be an easier way of locating a planet, surly?

Any ideas anyone?  because it’s driving me nuts and and I’m trying to get the hang of my new Zwo.

The Telrad is ok for finding alignment stars, but must be aligned with your telescope eyepiece, daytime is best to get this accurate.

 

[Moonshed]

32 minutes ago, Planitair said:

The Telrad is ok for finding alignment stars, but must be aligned with your telescope eyepiece, daytime is best to get this accurate.

 

Yes, I know.  I have aligned the Telrad to Telrad utter perfection with the telescope eyepiece. The precision I have achieved is the fantasy dream of the original Telrad designers and if I say so myself, and I do, it is so incredible, so unbelievably perfect, so superhuman in its execution, I have nominated myself for the Nobel Prize in Twiddling and Fiddling. My family backs my nomination wholeheartedly. 😄

Thanks for your help. I hope you realise this is just for a little light hearted relief and is in no way actually making fun of your comment which in fact is a very valid point. Sometimes this hobby can become somewhat frustrating.

Edited November 8, 2020 by Moonshed

[Moonshed]

42 minutes ago, dark knight said:

Since your already using a laptop (presumptuous of me i know) why not try plate solving and APT or nina, im totally converted to using plate solving now

I understand that plate solving is a very accurate method for PA. The thing is I use a PoleMaster and achieve very accurate PA and use APT for star focusing and setting subs etc.. The part that I have difficulty with is actually finding Mars, either using the mount’s GOTO or the Telrad. I expect plate solving may help with the precision required to locate a planet but is yet another thing I would have to master, having only this week started using my new ZWO, using FireCapture and using AutoStakker, it’s been a bit of a heavy week to be honest.

I am expecting that by using a flip mirror with an illuminated reticle eyepiece my problem will be resolved and I will be able to find Mars and also achieve good focus on it too.

Many thanks for your advice though, noted.

[dark knight]

If your already using APT, it has the ability to plate solve built in just need to download the platesolving star catalogues, it enables much more than PA, it tells exactly where your telescope is pointing and can be used by APT to sync your mount to any celestial object and put it in the center of your field of view

[PeterCPC]

I don't find that you need to use an illuminated reticule EP with the flip mirror. You can centre the planet quite easily.

[Moonshed]

1 hour ago, PeterCPC said:

I don't find that you need to use an illuminated reticule EP with the flip mirror. You can centre the planet quite easily.

Okay Peter, thanks for that, thought I would have to fork out even more money, glad to see it’s unnecessary.

[Moonshed]

9 hours ago, dark knight said:

If your already using APT, it has the ability to plate solve built in just need to download the platesolving star catalogues, it enables much more than PA, it tells exactly where your telescope is pointing and can be used by APT to sync your mount to any celestial object and put it in the center of your field of view

Thank you for that info, it’s something I will definitely have a go at because it sounds so good. 

[ollypenrice]

The problem remains that the moving mirror focus system is fundamentally unsuited to planetary imaging with its incredibly critical focus. Any adjustment shoots the planet off the chip. The electronic drawtube focuser is the ideal solution but a manual drawtube focuser also works well.

Olly

[michael.h.f.wilkinson]

The best way to get a planet on a small chip is using a flip mirror. I align my finder scope with the main scope with a reticle EP in place, then aim the scope at the planet with the finder scope, centre it on the cross hair of the EP in the main scope, flip the mirror up, and the planet is neatly on chip. It does help that I added an R&P focuser to the scope, but I also used this approach without.

 

[michael8554]

First of all, Mars isn't hard to find, it's not an "invisible" target like most DSOs.

Finding an "invisible"  DSO on a large-chip camera at common FLs is a good candidate for Plate Solving.

But centring a planet on a 1/3" chip at F20 to F30 or so, is much much more difficult.

Think about it. The tiny dot that is the planet only has to be a 1/3" off centre to miss the chip completely !

Michael